We are continuing our exploration of the chemistry of specifically designed nitrogen heteromacrocycles in order to ascertain their potential as biological models. Our research is designed to create new synthetic routes of pyridine-containing heteromacrocyles which possess a rigid non-flexible framework of known structural constraints which are similar to the corrin and porphyrin skeletal backbone, to determine the selectivity of metal ion coordination and general ligand potential of these new ligands vs those from natural sources, and to ascertain the unique electronic and structural relationships of these new bio-models.